Related Experiment Video
Updated: Aug 7, 2026

Multi-electrode Array Recordings of Human Epileptic Postoperative Cortical Tissue
Published on: October 26, 2014
Methsuximide reduces valproic acid serum levels
F M Besag1, D J Berry, M Vasey
1St Piers Lingfield, (Now The National Centre for Young People With Epilepsy) Surrey, England, UK. FBesag@aol.com
Abstract:
The authors investigated whether methsuximide affects serum levels of valproic acid. Pre-morning-dose serum valproic acid levels were measured in 17 patients (12 male, 5 female; age range, 8-19; mean, 14.5 years) who either started or stopped taking methsuximide but whose dose of valproate and other medication remained unchanged. Four of these patients both started and stopped taking methsuximide. For the whole group the mean valproic acid level (+/- standard error) while not taking methsuximide was 81.9 +/- 5.3 mg/L and while taking methsuximide was 55.7 +/- 4.3 mg/L. The difference between the means was highly significant (paired t test, p < 0.001). The mean valproic acid serum level before taking methsuximide was 85.4 +/- 4.5 mg/L (14 patients), which decreased to 58.2 +/- 4.8 mg/L while taking methsuximide (difference highly significant, p < 0.001). In the eight patients who stopped taking methsuximide the mean serum level increased from 49.8 +/- 7.5 mg/L to 71.7 +/- 8.5 mg/L (difference significant p = 0.025). Because methsuximide reduces valproic acid serum levels, it may be necessary to increase the valproate dose when methsuximide is added or reduce the valproate dose when methsuximide therapy stops, to avoid loss of seizure control or valproate toxicity respectively.
More Related Videos
11:53An Alternative Culture Method to Maintain Genomic Hypomethylation of Mouse Embryonic Stem Cells Using MEK Inhibitor PD0325901 and Vitamin C
Published on: June 1, 2018
03:07Modification of the Treatment Methods for Wasting Marmoset Syndrome with Tranexamic Acid and Supportive Measures
Published on: July 12, 2024
Related Concept Videos
Antiepileptic Drugs: Sodium Channel Blockers
Sodium channel blockers modulate ion channels, particularly voltage-gated sodium channels. They block only sodium ion movement.
Among the most commonly prescribed antiepileptic drugs are...
Antiepileptic Drugs: GABAergic Pathway Potentiators
The key GABA pathway potentiators used in epilepsy management are as follows.
Benzodiazepines are a well-known class of drugs used for their...
Antiepileptic Drugs: Modulators of Neurotransmitter Release Mediated by SV2A Protein
SV2A is a transmembrane glycoprotein located predominantly in the brain, modulating the release of neurotransmitters for neuronal communication. Both levetiracetam and brivaracetam exhibit a high affinity for...
Acid Suppressive Drugs for Peptic Ulcer Disease: Proton Pump Inhibitors
Gastric acid, a potent cocktail of hydrogen and chloride ions, is produced in specialized parietal cells within the...
Phase I Reactions: Oxidation of Aliphatic and Aromatic Carbon-Containing Systems
Oxidation reactions are fundamental in aromatic carbon-containing systems. An example is the hydroxylation of phenobarbital, a process that transforms it into...
Phase II Reactions: Methylation Reactions
The mechanism of methylation unfolds in two stages. The first stage sees a methyltransferase enzyme facilitating the transfer of a methyl group from S-adenosylmethionine (SAM) to the substrate, forming S-adenosylhomocysteine (SAH). The second stage involves further metabolism of SAH into homocysteine, which can be recycled...